Amano shrimp (Caridina multidentata): the algae-eating champion
The biggest and hardest-working aquarium shrimp: 4–6 cm, eats black beard and hair algae, doesn't breed in freshwater. Parameters, feeding, pitfalls.
The amano shrimp (Caridina multidentata) was popularised by Takashi Amano, the legendary Japanese aquascaper, as the living 'janitor' of his showcase planted tanks. Translucent grey, 4–6 cm long, with algae-processing speed 5× a cherry shrimp's. This shrimp is for work, not for breeding: its larvae need brackish water and die in regular tanks.
Parameters and tank size
Minimum 38 L for 3, optimum 60–100 L for a group of 6–10. Temperature 20–27 °C, pH 6.5–7.8, gH 4–14. Far less picky on parameters than cherries — they tolerate even soft slightly acidic water that suits plants. 25% weekly water changes.
What algae they eat
Their big strength: they eat what cherries and nerites won't — black beard algae (BBA), hair algae, sometimes even film cyanobacteria. They also clean up dying plant leaves and food leftovers. They won't fully clear BBA but will weaken it enough for water changes and reduced lighting to finish the job.
Feeding and starvation risks
In an algae-free aquarium (a mature CO₂ scape) amanos start chewing tender plant leaves — mosses, small cryptocorynes. Supplementation is mandatory: 2–3 times a week a piece of blanched cucumber or zucchini, or shrimp tablets. With enough food they leave plants alone.
Tankmates
Compatible with all peaceful fish: guppies, neons, tetras, rasboras, corydoras, otocinclus, angelfish (will eat juveniles but can't catch adults), bettas (a risk for amanos — they may attack). Cardinals and large tetras usually ignore them. NOT compatible: cichlids, big catfish, gouramis, anything that can swallow a 5 cm shrimp. More in our [compatibility handbook].
Why they don't breed at home
Amanos are amphidromous. The female carries 1000–3000 tiny eggs for 5–6 weeks; after hatching the veliger larvae drift to estuarine brackish water and develop there for 30 days before becoming juvenile shrimp. In a freshwater tank larvae die in 2–3 days. Breeding is possible but needs two tanks (fresh + brackish) and dedicated gear — uneconomical for most.
If you have a planted tank with an algae problem and no predatory fish, amanos are a literal miracle cure. A pack of 10 in a 100 L tank restores balance in 2–3 months.
Lifespan and price
In an aquarium — 2–5 years. US/EU prices: $3–5 per shrimp when buying 10+. The biggest killer is shipping with sharp TDS swings — drip acclimation over 3 hours is mandatory. More on alternative algae-control methods — in our [algae control guide].
FAQ
- How many amanos per tank?
- 1 shrimp per 10–15 L for active algae control. In a 60 L — 4–6, in a 100 L — 8–10. Fewer and algae stay; more and they starve and start chewing plants.
- What if an amano 'jumps out' of the tank?
- Their ability to climb tubes is a myth. The real cause is an open lid plus a sharp drop in TDS or temperature. Solution: always a tight lid, gradual acclimation after water changes.
- Can I keep amanos with cherries?
- Yes, fully compatible and non-competitive (amanos work on 'hard' algae, cherries on biofilm). But an adult amano will occasionally eat a freshly moulted female cherry — provide hiding spots for moulting.
Goldie editorial team
Practising aquarists with a combined 30+ years of experience · Biologists and editors, fact-checking against FishBase and Seriously Fish · Every piece is reviewed by a qualified ichthyologist before publication
PhD in ichthyology, researcher of African Great Lakes cichlids
PhD in ichthyology, University of Edinburgh · Field research in Malawi, Tanganyika and Victoria (2013–2018) · 12+ peer-reviewed publications on cichlid behaviour
Sources
- Seriously Fish — Caridina multidentata · Seriously Fish · 2026-10-30
- Tropica — Algae control with shrimp · Tropica · 2026-10-30
- Practical Fishkeeping — Amano shrimp · Practical Fishkeeping · 2026-10-30